The present disclosure relates to an apparatus and method for controlling a temperature, and more particularly, to an apparatus and method for controlling a temperature that may isolate each channel of a temperature sensor.
A programmable logic controller (PLC) may include a temperature control device for temperature control and the temperature control device may use an input module and an output module.
The temperature control device may occupy a PLC base slot for each of the input module and the output module, in which case the temperature control device may occupy two PLC base slots and there is inconvenience in independently setting the operation of each module.
When in order to such a limitation, a module occupying one PLC base slot includes temperature input, PID calculation and transistor output functions, it is possible to decrease complexity and inefficiency. In this case, it is possible to solve limitations that PID control performance is affected by the scan time of a PLC CPU and temperature control stops when the PLC CPU has an error.
For such a temperature control device configured to occupy only one slot, it is desirable to secure isolating characteristics for each input channel at the industrial site, in which case the same hardware is configured for each channel in order to secure isolation for each input channel and much cost is required for module configuration.
In particular, analog products require an inter-channel working voltage for many industrial applications. Thus, a product using a multiplexer may overcome constraints of manufacturing cost and space but it is difficult to satisfy the inter-channel working voltage. In addition, a product configured to have isolation for each input channel may present the inter-channel working voltage but it has significant limitations in constraints of manufacturing cost and space.